The Mid-Ohio Athletic Conference is an OHSAA athletic league whose members are located in the Ohio counties of Crawford, Marion, and Richland. The league was established in the fall of 1990.
The MOAC was established in time for the 1990-91 school year. The divisions were created to align schools based on size, and every sport recognizes a champion for each division.
- The four Marion County schools (Elgin, Pleasant, Ridgedale, and River Valley) were members of the North Central Conference prior to joining the MOAC.
- The four Morrow County schools (Cardington-Lincoln, Highland, Mount Gilead and Northmor) were members of the now-defunct Mid-Ohio Conference before agreeing to join the MOAC.
- Buckeye Valley (Delaware Co.) and North Union (Union Co.) were members of the now-defunct Central Buckeye League before joining the MOAC.
In April 2011, the league considered expanding up to six members. Four of the schools considered were from the Mid-Buckeye Conference: Centerburg, Danville, East Knox, and Fredericktown; the other two schools mentioned were Fairbanks and Marion Harding.
In May 2011, the league received formal applications from seven schools. These included Centerburg, Danville, East Knox, and Fredericktown from the Mid-Buckeye Conference; Marion Harding from the Greater Buckeye Conference; Fairbanks from the Northwest Central Conference; and Jonathan Alder, which was an independent. Four invitations were extended only to Centerburg, Fredericktown, Fairbanks, and Jonathan Alder. By June 2, all four schools had verbally agreed to join the league for the 2013-14 school year.
On December 1, 2011, Ridgedale announced it would leave the MOAC to help form the new Northern 10 Athletic Conference in 2014 with members from the North Central Conference and the Midland Athletic League.
Both Upper Sandusky and Galion were invited to join the league in early 2012 as Red Division members, with both expected to replace Ridgedale and join in 2014. However, in June 2013, Upper Sandusky took advantage of an opening in the N10 and joined that league in all sports except football for 2014. The Upper Sandusky Rams played football as a MOAC school for 2014 only before fully joining the N10. East Knox accepted the offer to be the eighth member of the Blue Division for 2014.
On August 5, 2013, Marion Harding was extended an invitation to replace Upper Sandusky in 2015-16 pending a vote of approval from Harding's school board. On August 20, 2013, the league announced Marion Harding had accepted the offer to join. Eventually, Marion Harding's membership was moved up to joining during the 2014-15 school year as Upper Sandusky competed in the MOAC for football only in 2014.
When all of the new members joined by 2014, the league continued to be split into divisions of Red and Blue.
In April 2015, Fairbanks announced that they would be leaving the MOAC to join the Ohio Heritage Conference, along with independent Madison Plains.  They plan to begin play in the 2016-2017 school year.
In November 2015, seven schools from the Blue Division (Cardington, Centerburg, East Knox, Fredericktown, Highland, Mount Gilead, and Northmor) announced that they would withdraw from the MOAC to form a new league with Danville of the MBC. This new league would later be branded the Knox Morrow Athletic Conference. Per the MOAC constitution, the schools must stay through the 2017-18 season, although it could happen a year sooner than that.
Likely due to the Blue Division's demise, Elgin and the Northwest Central Conference announced in December 2015 that the Comets would join the NWCC in 2017-18 as a full-member.
In February 2016, Jonathan Alder announced they would be leaving the MOAC for the Central Buckeye Conference in 2017-18.
In March 2016, Ontario announced that they would join the MOAC in 2017-18 when the Northern Ohio League disbands. Clear Fork is also joining at the same time as they were voted out of the Ohio Cardinal Conference following the 2017-18 school year.
In July 2017, North Union announced they would be leaving the MOAC for the Central Buckeye Conference. This prompted the league to invite Shelby as a replacement, which their school board accepted. North Union will remain in the MOAC for football through the 2019-2020 year but will switch to the CBC in all other sports for the 2018-2019 year. Shelby will do the same staying in the SBC for football through the 2019-2020 year but will switch to the MOAC in all other sports for the 2018-2019 year which means Shelby will only spend one year in the Sandusky Bay Conference and only two for football.
In February 2018, Buckeye Valley announced they would be leaving the MOAC for the Mid-State League Ohio Division. The league invited Highland to fill the spot but Highland declined. The MOAC has decided not to rush to find an eighth member, content to stay at seven once BV leaves. 
League champions 
The MOAC supports 12 league sports for both male and female competition. This includes football, boys' and girls' basketball, boys' and girls' track & field, boys' and girls' cross country, baseball, softball, volleyball, wrestling, and golf.
League champions for each sport are recognized in both the Red Division and Blue Division, with the exception of wrestling until 2004. The MOAC also awards an all sports trophy as well. |}